SS304 Tube Sheet
The baseline stainless grade — general corrosion resistance without molybdenum, the right choice whenever the fluid service doesn't specifically call for chloride pitting resistance and the joint won't be welded.
Chemical Composition
| Element | Min % | Max % |
|---|---|---|
| Chromium (Cr) | 18.0 | 20.0 |
| Nickel (Ni) | 8.0 | 10.5 |
| Carbon (C) | — | 0.08 |
| Manganese (Mn) | — | 2.0 |
| Silicon (Si) | — | 0.75 |
Mechanical Properties
| Property | Typical Value |
|---|---|
| Tensile Strength | 515 MPa min |
| Yield Strength (0.2% offset) | 205 MPa min |
| Elongation | 40% min |
| Brinell Hardness | 201 HB max |
Equivalent Grades
| Standard | Designation |
|---|---|
| ASTM / UNS | S30400 |
| EN / DIN | 1.4301 |
| JIS | SUS304 |
SA-965 / F304 Specification
When a drawing or RFQ cites SA-965 / F304 (or ASTM A965 Grade F304) with UNS S30400, it is pointing at an austenitic stainless-steel forging path — not a universal “tube sheet standard.” Confirm the ordered product form, grade designation and purchaser requirements against the drawing before procurement.
| Element | Reference |
|---|---|
| Specification | ASTM A965 / A965M |
| ASME designation | SA-965 / SA-965M where applicable (edition-dependent; confirm Code context) |
| Grade designation | F304 |
| UNS | S30400 |
| Product form | Austenitic stainless-steel forging |
| Application context | Pressure and high-temperature parts, subject to project requirements |
A965/SA-965 covers austenitic stainless-steel forgings for boilers, pressure vessels, high-temperature parts and associated equipment. F304 is the listed grade designation that corresponds to UNS S30400 (SS304). The finished tube-sheet geometry, machining, hole pattern and inspection scope remain purchaser / drawing requirements — they are not defined by naming A965 or SA-965 alone.
Do not treat A240, A182 and A965 as interchangeable. A practical procurement path when SS304 / F304 / S30400 appears on a drawing:
| Specification | Product form / role | How to read it for tube sheets |
|---|---|---|
| ASTM A240 / SA-240 | Plate, sheet and strip | Common plate path when the blank is machined from flat product |
| ASTM A182 / SA-182 | Forged / rolled piping components (F304 context) | Relevant when the callout is piping-component forging scope; confirm against the ordered part — do not assume A182 purchases a large forged tube-sheet blank |
| ASTM A965 / SA-965 | Austenitic stainless-steel forgings (F304) | Investigate when the material is specified as a forging for pressure/high-temperature parts |
For RFQ clarity, include where known: grade (SS304), UNS (S30400), ASTM/ASME + edition, F-grade (F304), product form (plate / forging / clad), drawing + revision, OD/thickness, hole pattern, quantity, and inspection/testing.
Continue from grade identity into product form and machining:
304 vs. 304L — Which One
Available Product Forms
SS304 is offered across all structural types — Fixed, Floating, and U-Tube — and is the most commonly stocked grade in standard diameters.
Applications
General chemical processing, HVAC-adjacent process cooling, and light industrial service where fluid chemistry doesn't demand molybdenum's chloride resistance. For welded joints in the same service class, see SS304L; for chloride-bearing fluids, see SS316L.
Advantages & Limitations
Advantages
- Lowest cost within the stainless family
- Widest stock availability, shortest lead times
- Well understood, easy to machine and fabricate
Limitations
- No molybdenum — limited chloride pitting resistance
- Weld sensitization risk without post-weld treatment
- Not suitable for seawater or high-chloride service
FAQ
304 is widely used in potable water systems and is generally considered food-safe, though specific approvals (e.g. NSF, WRAS) depend on the destination market's regulatory requirements — confirm the specific certification needed for your project.
316 isn't universally better — it's better specifically at chloride resistance, which costs more. If your fluid service has no meaningful chloride content, 304 delivers the same general corrosion resistance at a lower price with no real trade-off.
304 is our most widely stocked grade across common diameters given its high demand volume. Confirm your specific size and thickness for immediate availability.